Platt is evidently playing a mysterious character simply known as "The Man in Black"; Deadline.com reports that this character is not a mutant, so perhaps he'll be acting in a similar capacity to Brian Cox's villainous human in X2.
Meanwhile, Flemyng will play an alternate dimension-dwelling mutant named "Azazel", who in Marvel lore is the father of "Nightcrawler". (Nightcrawler was played by Alan Cumming in X2, although it's unknown if the character will be in First Class). Azazel, according to Marvel.com, can teleport by opening a portal into another dimension, travel through it, and return via another portal back to his originating dimension. While in this other dimension, Azazel can manipulate its energies to open small viewing portals to Earth or generate devastating energy blasts. Sounds like a dude with whom you don't want to screw.
Platt and Flemyng are just the latest names added to the First Class roster, which include James McAvoy (Professor X), Michael Fassbender (Magneto), Nicholas Hoult (Beast), Caleb Landry Jones (Phoenix), Alice Eve (Emma Frost), Jennifer Lawrence (Mystique), Edi Gathegi (Darwin), Kevin Bacon (the still-unnamed villain), Lucas Till (Havoc) and the newly announced Rose Byrne (Moira McTaggert). Matthew Vaughn is directing from a script written by Jane Goldman and Jaime Moss.
Do you think the production is cutting it kind of close, with well under a year to go before the film has to be completed?